Apologies if this is blindingly obvious, but I have searched the menu's high and low to try to find a way to disable the alarming 'spang' noise whenever a new METAR or TAF is detected. 
I can appreciate the value of the 'Wind Turbine Ahead' or 'About to enter class A airspace' alarms, and for exactly those reasons, I don't want to have to turn down the volume on my device. The 'new Metar received' warning (although a different sound) sounds every bit as urgent, and frankly makes me leap out of my seat… Is there any way of turning it off?

Otherwise a wonderful app - particularly like the X-Plane link-in for rainy days!

There isn't, I'm afraid.

There is a workaround:

just disable your Mobile Data connection.... your iPad (or other device) won't receive any more updates now....
(warning: don't forget to 'pre-download' your plates... cached plates a slightly colored green)


kindest reg.

Robert